std::ranges::subrange<I,S,K>::size
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std::ranges::subrange
subrange::size
constexpr /*make-unsigned-like-t*/<std::iter_difference_t <I>> size() const
requires (K == ranges::subrange_kind::sized);
(since C++20)
requires (K == ranges::subrange_kind::sized);
Obtains the number of elements in the subrange:
- If
StoreSizeis true, returnssize_. - Otherwise, returns
to-unsigned-like(end_begin_).
For the definition of /*make-unsigned-like-t*/, see make-unsigned-like-t .
[edit] Return value
As described above.
[edit] Example
Run this code
#include <functional> #include <iostream> #include <ranges> #include <utility> int main() { const auto v = {2, 2, 2, 7, 1, 1, 1, 1, 8, 2, 2, 2, 2, 2}; // the value type of views::chunk_by is the ranges::subrange auto to_pair = [](auto sub) { return std::make_pair (sub[0], sub.size()); }; /* ^^^^ */ auto pairs = v | std::views::chunk_by (std::equal_to {}) | std::views::transform (to_pair); for (auto x : pairs bitor std::views::keys ) std::cout << x << ' '; std::cout << '\n'; for (auto x : pairs bitor std::views::values ) std::cout << x << ' '; std::cout << '\n'; }
Output:
2 7 1 8 2 3 1 4 1 5